Crown grinder



March 21, 1961 M. 1. RUDNICKI ETAL 2,975,562

CROWN GRINDER 5 Sheets-Sheet 11 Filed May 5, 1958 rail INVENTORS MARKLRUDNICKI By WILHELM DRALLE Wm #044 14 ATTORNEYS March 21, 1961 M.RUDNICKI ETAL 2,975,562

CROWN GRINDER Filed May 5, 1958 5 Sheets-Sheet 2 INVENTORS MARK I.RUDNICKI WILHELM DRALLE ATTORNEYS 5 Sheets-Sheet 3 CROWN GRINDER M. l.RUDNICKI ETAL m m m m N m L W W p u M N R hm mm mm b mm tm mm N C M wmum mm 0mm A C, wmw m om mm \A 0 w mm w QW m Om w ON Manch 21, 1961Filed May 5, 1958 ATTORNEYS March 21, 1961 M. l. RUDNICKI ETAL CROWNGRINDER Filed May 5, 1958 5 Sheets-Sheet 4 INVENTORS MARK l. RUDNICKI BYWILHELM DRALLE ATTOR N EYS March 21, 1961 M. RUDNICKI ETAL 2,975,562

CROWN GRINDER 5 Sheets-Sheet 5 Filed May 5, 1958 m N2 mm LUQ mm. m2

wm. N2 Nw mm oom 1 Now or NH \T N: m9 6 0C Oh. v9

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INVENTORS MARK I.RU DNIGKI ATTORNEYS "track:

2,975,562 CROWN onnvnnn Mark I. Rudnicki, Harper Woods, and WilhelmDralle, Detroit, Mich., assig'nors, by mesne assignments, to Ex-Cell-OCorporation, Detroit, Mich., a corporation of Michigan Filed May 5,1958, Ser. No. 732,974

' 14 Claims. (Cl. 51-63) the same preset crown radius.

Other objects and features of the invention will become apparent as thedescription proceeds, especially when takenin conjunction with theaccompanying drawings, illustrating a preferred embodiment of theinvention, wherein:

Fig.1 is a front elevational view of a grinding machine embodying theinvention.

Fig. 2 is a viewtaken on the line 2-2 of Fig. 1.

Fig. 3 is a sectional view taken on the line 33 of Fig. 1. i

) Fig. 4 is a diagrammatic view of the motor for oscillating thegrinding wheel.

Fig. 5 is a View partly in section ofthe down feed mechanism.

Fig. 6 is a diagrammatic View illustrating the hydraulic operatingsystem.

Fig. 7 is a sectional view taken on the line 7--7 of Fig.

United States Patent 6 6, illustrating the locking valve for thehydraulic operating mechanism.

Fig. 3 is a Wiring diagram.

Referring now more particularly to the drawings, the machine comprises abed 10 on which is supported a reciprocable table 12. A work support ismounted on the table, including a head stock 14 and a tail stock 16having centers 18 for engaging an arbor on which the gear G to be groundis mounted. There is also an indexing mechanism (not shown). forperiodically rotating the arbor step by step. Agrinding wheel dresser 20is mounted on the table." i V A pair of columns 22 and 24. extendupwardly from the bed at the rear of the table, and the adjacentsurfaces ofthe columns are spaced apart and define parallel vertit tendshorizontally and at right angles to the path} of movement of table 12,and 'is journalled for rotation in the support block by bearings 32.generally vertical arm 3 4 is carried by 'the shaft 30 to oscillate asaunit therewith The -arm 34 has a transverse flange dhi forr'ried hfarecess '37 forreceivingthe flange 38 Lon the end "has longitudinallyextending dovetail. A motorjmount 44' is formed witha recess s eg w til.

hea

i530.The flange is secured within the recess by jack to, permit slidingmovement m bearings 116 and 113.

shaft 30 and at right angles to the path of movement of t the table.

The arm 34 carries a longitudinally extending elongated screw 52 whichis mounted on the arm for free rotation by the handle 54 at the upperend but which is held against longitudinal movement relative to the arm.The screw engages a nut 55 secured to the motor mount so that rotationof the screw will result in movement of the motor mount lengthwiserelative to the arm 34. An automatic dress feed device 56 is secured tothe lower end of the arm and is operatively connected to the screw 52.This invention is not concerned with the automatic dress feed device andtherefore it will not be described in detail. The automatic dress feedprovides a means for automatically rotating the screw 52 to move thegrinding wheel during the dressing operation.

The shaft 30 is oscillated by an oscillating motor 60 mounted on abracket 62 carried by the support 28. The motor is diagrammaticallyillustrated in Fig. 4 and comprises the housing 64 supportingtherewithin a shaft 66 for rotation. The shaft 66 has secured to it avane 68 adapted to oscillate Within the arcuate fluid chamber 70. Whenfluid under pressure is alternately admitted to opposite ends of thischamber through ports 72 and 74 via lines .76 and 78, the vane 63 andshaft are oscillated back and forth. Hydraulic fluid under pressure isalternately;ajdmitted to lines '76 and 78 by the 4-way valve 80 from ahydraulic line 32. The lines 76 and 78 are alternately exhausted by thevalve through exhaust line 84. The valve is controlled by solenoids 86and 88. Motor shaft 66 is secured to shaft 30 by coupling 87.

The mechanism for vertically moving the shaft support 28 comprises ascrew threaded rod 90 and a nut 92 on the shaft support threadedlyreceiving the rod. The rod is supported at its upper and lower ends forrotation and vertical or axial reciprocation. At its upper end as shownin Fig. 5, the rod has a splined section which is splined to a sleeve 4so that the rod and sleeve rotate as aunit but may move axially relativeto one another. The sleeve is held against axial movement by the framestructure 101. A bevel gear 1% is secured to the sleeve and meshes witha bevel gear 162 carried by a shaft 104 which is operated by a handle106 for the manual rotationof the rod 90. Thus the handle 166 may beemployed to shift the shaft support 28 vertically. This mechanism may beused not only for the initial adjustment of the grinding .wheelintooperative relation to the work (gear G) but also for manuallyfeeding the grinding Wheel step by step. Where it is so used, the screwthreaded rod 90 is held against axial movement and consequently willimpart movement to the shaft support 28 by its rotation in the nut 92.

However, in the automatic feed the rod 90 is moved axially by amechanism now to be described. The rod 98 at'its upper end is supportedfor axial as well as rotary movement. Its lower end is similarlyjournalled in the bed offthe machine. The automatic feed mechanism isindicated generally at 112 and includes a member 114 which is swiveledupon the rod 90 by end thrust roller These bearings prevent any relativeaxial movement between the rod 90 and the member 114 while permittingfree relative rotation.

therethrough of a horizontal shaft 130 which is suitably journalled forrotation within the housing 122. The shaft 130 has an eccentric portion132 on which the member 128 is mounted. Thus the rotationof the shaft131 in the housing 122 will through the eccentric 132 and connecting rodmember 128 impart an axial movement to the member 114 and shaft $6.Beyond the eccentric 132 the shaft 130 has a concentric portion on whichis mounted a pinion 136. The pinion is in mesh with a rack member 138which has on opposite ends thereof piston portions 149 and 142 engagingin hydraulic cylinders 144 and146 which are mounted on opposite sides ofthe housing 122 by bolts 148.

Before further description of the apparatus, it may be stated that thefeeding movement of the grinding wheel is effected by an axial movementof the screw threaded rod 90 which, in turn, is accomplished by arotation of the shaft 130 causing the eccentric portion 132 thereof tomove the connecting rod member 128 and member 114.

The rotation of the shaft 131) is accomplished by a movement of thepistons 1411 and 142, which movement is controlled by admission ofhydraulic fluid to one of the cylinders and expulsion of fluid from theother cylinder. Consequently, the amount of feeding movement must becontrolled by accurately metering the fluid entering and "leaving thecylinders 144 and 146.

Generally described, the hydraulic operating system includes a source ofhydraulic fluid under pressure, a valve controlling the admission offluid alternately to the cylinders .144 and 146, a metering meansconnected to the cyl1nder-144 operating to successively ejectpredepropelling the fluid from the tank through an outgoing conduit 156and a relief valve 158 which returns the "unused fluid to the tank whilemaintaining a predetermined constant pressure on the line 156. The line156 has a branch 160 extending to the cylinder 146 and a second branch162 leading to the metering device 164. In'the line 156 is anelectromagnetically operated valve 166 and in the branch 162, anelectromagnetically operated valve 168. A conduit 170 extends from thecylinder 144 to the metering device and in this conduit is a normallyclosed and locked check valve 172. The valve 166 normally opens theconduit 156 to maintain hydraulic pressure on the fluid in the cylinder146 but in another position of this valve, fluid is exhausted from thecylinder 146 to be returned to the tank 156 while pressure fluid issupplied through a conduit 174 to the c linder 144. A check valve 176linthis conduit prevents movement th'erethrough in the opposite direction.The valve 168 normally opens the branch conduit 162 to supply fluidthrough a portion 178 thereof to one end of the cylinder'of.the'metering device 164(as will be hereinafter explained), while inanother position of the valve 168; the conduit portion 178 will beconnected to an exhaust conduit 18 returning'fluid to the-tank. In thelatter position of the valve 168, the

branch conduit 162 is connected to a conduit 182 leading to the checkvalve 172 and functioning to unlock. and

open the valve. There is also a conduit 184 leading from Y the conduitportion 176 to the conduit 182. but

containing a check valve 186 which prevents movement offluid'therethrough in the reverse direction. In the 'n'ormal'lpositionof the valve 168, boththe conduits 182 and 184 are connected with the'exhaustconduit i The metering device 164 comprises a cylinder 183containing a free piston-19ti, the amplitude of movement of 'which, islimited by an adjustable stop 192, The conduit l7 lconn ectswith the endof the cylinder containing the 192, whilethe conduit 17% is connected tothe. opib'bsiteiid of the cylinder. Thus normally pr essiire fluid 4 inthe conduits 162 and 174 holds the piston 190 against the stop 192.

The check valve 172 has a spring 194 for normally holding the valveelement 196 seated as illustrated in Fig. 7. There is however a piston198 in a cylinder 2th) connected to the conduit 182 and this piston whenactuated will press a rod 202 against the valve element to unseat thesame.

The operation of the hydraulic system as thus far described is asfollows:' Fluid under pressure fills both of the cylinders 144 and 146to press against pistons 142 and 144 therein and hold the rack member133 against movement. This stationary position of the parts is assuredas the check valve 172 is locked from opening which prevents any escapeof fluid from the cylinder 144, while the cylinder 146 is in opencommunication with the conduit 156 containing the pressure fluid.Assuming that the valve 168 is operated, the valve 166 remaining innormal position, this will first connect the conduit 162 with theconduit 132 thereby unseating the check valve 172. Also, the conduit 178will be connected to the exhaust conduit 180. Consequently, the piston190 is free to move in the cylinder 183 under pressure of fluid expelledfrom the cylinder. 144 and passing into the metering device through theconduit 170 and open check valve 172. caused by the pressure of fluid inthecylinder 146 which actuatcs the istons 142 and 144 and moves the rack138 a corresponding distance. If the valve 168 is then restored tonormal position, the valve 172 will be closed and locked and pressurefluid will enter the metering cylinder 18% through the conduit 178returning the piston 1% to its position against the stop 192 andexpellingfluid from the opposite side of said piston through the conduitshaft 139 causing the eccentric 132 and connecting rod member 128 tolower the member 114 and screw threaded rod 91 This will feed thegrinding wheel into the work a predetermined amount, and in successiveoperations of the valve 168 the grinding wheel willbe fed stepby step toa predetermined limit. The valve 166 will then be operated (throughcontrol means hereinafter described) which will connect the cylinder 144with the pressure line 156 and the cylinder 146 with the exhaust linethereby returning the rack 138 and themechanism connected therewith tonormal position.

In operation, and with a gear mountedon an arbor carried by centers 18,the grinding wheel will be oscillated back and forth across thegearthrough an interdental space of the gear to fashion the teeth onopposite sides thereof to the contour of the formed-grinding wheel. Thecrown radius ground on the gear teeth will equal the distance betweenthe axis of rotation of the oscillating sides of a vertical positionsufficiently to clear the gear at either limit. At each limit ofoscillation of the grinding Wheel, the shaft support 28 is indexeddownwardly a small increment to feed the wheel into the work stepbystep.- V

Referring to ,Figs. 4 and 8, the oscillation of the shaft '30 andgrinding wheelis started by closing the .manual pushbutton 222;energizing relay: CR and closing contacts CR1 and CR2 to seal intherelay andusend current to the circuits 224 and 226. Thesecircuitscon- ,tain the. solenoids .86 and 88 which shift the valve its vast engaes limit switch 228 to energize solenoid 86 Such expulsion from thecylinder 144 is sending pressure fluid through line 76 and exhaustingline 78 to swing the'shaft 66 and its 'vane 68 to the other limitengaging limit switch 230. This reverses the fluid flow, sending fluidunder pressure through line 78 and exhausting line 76 to produce acontinuous oscillation of the grinding wheel about the axis of shaft 30.

, Limit switch 232 is closed at the same time that limit switch228 isclosed energizing the solenoid 234 of the electromagnetically operatedvalve 163 resulting in operation of the down feed mechanism to move thescrew threaded rod 90 down a step and correspondingly moving the shaftsupport 28 to feed the grinding wheel into the work. Limit switch 236 isclosed at the same time limit switch 230 is closed, likewise actuatingthe valve 168. Hence the grinding wheel is fed downwardly step by stepat each limit of oscillation of the grinding wheel.

When the shaft support reaches a predetermined lower limit of movement,it engages a limit switch 240 opening the switch to de-energize relay CRand open its contacts tone-energize the down feed mechanism andoscillating mechanism of the motor 60. Limit switch 240 has a secondcontact 241 which simultaneously closes to energize relay 242 of theelectromagnetically operated valve 166. This relay has a contact 243 forsealing in the circuit. As previously described, the operation of valve166 will connect the cylinder 144 with the pressure line 156 and thecylinder 146 with the exhaust, thereby actuating the rack 138 in thereverse direction rotating the shaft 130 to its initial position andreturning the shaft support 28 to its upper limit in which the grindingwheel is raised clear of the work. At is upper limit, the shaft supportopens limit switch 246 to de energize relay 242. t After the foregoingcycle of operation, the table 12 may be actuated to move the gear Cclear of the grinding wheel and to bring the grinding wheel dresser 20under the grinding wheel. The grinding wheel may then be fed downwardlyinto the dresser mechanism either by the automatic dress feed 56 or bythe manual rotation of the screw 52 by'the handle 54. Since the dresseris fixed in relation to the table, it will grind the peripheral contourof the grinding wheel without disturbing the crown radius dimension 220between the periphery of the wheel and the axis of rotation of shaft 30.Hence the diminishing diameter of the grinding wheel is automaticallycompensated for by this method of dressing, and the grinding wheel willcontinue to grind on the same radius in succeeding cycles.

After dressing, the table is returned to the illustrated position, thegear G is indexed to bring the next interdental space in register withthe grinding wheel, and the wheel may be initially moved down intooperative relation to the gear G by the manual rotation of the screwthreaded rod 90 by handle 106. Thereafter the manual pushbutton 222isclosed to initiate the automatic down feed. a

What we claim as our invention 'is:

1. In a grinding machine, a support, an arm rotatably carried by'saidsupport, a rotatable grinding wheel carried by said arm in spacedrelation to the axis ofrotation of said arm,'means for oscillating saidarm about its axis of rotation, and means for automatically moving saidsupport in a direction transverse to said axis between separateoscillations of said arm to feed said grinding wheel into a workpiece.

2. In a grinding machine, asupport, means for guiding said support formovement in opposite directions, a shaft rotatably carried by saidsupport having its axis extending transversely of the path of movementof, said support, an arm extending radially from said shaft and securedthereto for rotation as a unit therewith, a rotatable grinding wheelcarried by said arm in spaced relation to the axis of rotation of saidshaft and with its axis of rotation parallel to that of said shaft,means for oscillating said shaft, and automatic means for moving saidsupport in one direction between separate oscillations of said shaft tofeed said grinding wheel into a workpiece.

3. A machine as in claim 2, including means for adjusting said grindingwheel on said arm toward and away from the axis of rotation of said arm.

4. In a grinding machine, a support, means for guiding said support forvertical movement in opposite directions, a horizontal shaft rotatablycarried by said support, an arm fixed to said shaft and extendingradially therefrom in a generally upward direction, a rotatable grindingwheel carried by said arm in spaced relation above the axis of rotationof said shaft, means for oscillating said axis of rotation of said shaftand with its axis of rotation parallel to that of said shaft, means foroscillating said a horizontal shaft rotatably carried by said support,an

arm fixed to said shaft and extending radially therefrom in a generallyupward direction, a rotatable grinding wheel carried by said arm inspaced relation above the axis of rotation of said shaft and with itsaxis of rotation parallel to that ofsaid shaft, means for oscillatingsaid shaft to move said arm between limiting positions at opposite sidesof a vertical position, and means for moving said support downwardlywhen said arm is in a limiting position due to oscillation of said shaftto feed said grinding wheel into a workpiece.

6. in a grinding machine, a support, means for guiding said support forvertical movement in opposite directions, a horizontal shaft rotatablycarried by said support, an arm fixed to said shaft and extendingradially therefrom in a generally upward direction, a rotatable grindingwheel carried by said arm in spaced relation above the axis of rotationof said shaft and with its axis of rotation parallel to that of saidshaft, means for oscillating said shaft to move said arm betweenlimiting positions at opposite sides of a vertical position, and meansfor successively moving said support downwardly at each limitingposition in the oscillation of said shaft to feed said grinding wheelinto a workpiece.

7. In a grinding machine, a support, means for guiding said support forvertical movement in opposite directions, a horizontal shaft rotatablycarried by said support, an arm fixed to said shaft and extendingradially therefrom in a generally upward direction, a rotatable grindingwheel carried by said arm in spaced relation above the axis of rotationof said shaft and with its axis of rotation parallel to that of saidshaft, means for oscillating said shaft to move said arm betweenlimiting positions at opposite sides of a vertical position, and meansresponsive to movement of said arm for successively moving said supportdownwardly at each limiting position in the oscillation of said shaft tofeed said grinding wheel into a workpiece.

8. A machine as in claim 7, including: means for ad justing saidgrinding wheel on said arm toward and away from the axis of rotation ofsaid arm to vary the radius of oscillation ofsaid wheel.

9. In a grinding machine, a bed, a reciprocable table mounted onsaidbed, a work support mounted on said table including a head stock and atail stock, a center in each of said head stock and tail stock, an arborfor mounting a workpiece held by said centers, a pair of columnsextending upwardly from said bed in spaced relation to said table, asupport block located between said columns and guided thereby duringvertical movement therebetween, manually operable means associated withsaid support block to provide vertical movement thereof in oppositedirections between said columns, a horizontal shaft extending in atransverse. direction with respect to and extending radially therefromin a generally upward direction, a'motor mounted on said arm forvertical sliding movement therealong means for producin slidingmovementof said motor along said arm, a spindle secured to and driven by saidmotor, a grinding wheel mounted on said spindle in spaced relation abovethe axis of rotation of said shaft and with its axis of rotationparallel to that of said shaft, hydraulic means for automaticallyoscillating said arm about the axis of rotation of said shaft betweenlimiting positions at opposite sides of a vertical position, andhydraulic means responsive to the oscillation of said arm forautomatically moving said support downward a predetermined amountbetween said columns on said arm reaching each limiting position in theoscillation thereof to feed said grinding wheel into a workpiecepositioned on said arbor while maintaining the radial dimension betweenthe shaft and spindle so'that a crown having a predetermined surfacecontour will be formed on said workpiece.

10. In a grinding machine, a bed, a work support mounted on said bed,guide means mounted on said bed in spaced relation to said work support,a support block positioned adjacent said guide means for guided movementthercalong, a horizontal shaft extending in a transverse direction withrespect to said work support and rotatably carried by said supportblock, an arm fixed to said shalt extending radially therefrom in'agenerally upward direction, a rotatable grinding wheel mounted on saidarm in spaced reiation above the axisof rotationof said shaft and withits axis of rotation parallel to that of said shaft, means forautomatically oscillating said arm about the axis of rotation of saidshaft between limiting positions at opposite sides of a verticalposition, and means responsive to the oscillation of said arm forautomatically moving said support block downward a predetermined amounton said arm reaching each limiting position in the oscillation thereofto feed said grinding wheel intoa workpiece positioned on said worksupport while maintaining the radial dimension between the shaft andgrinding wheel so that a crown having a predetermined surface contourwill he formed on said workpiece.

11. In a grinding machine, a bed, a work support mounted on said bed,guide means mounted on said bed in spaced relation to said work support,a support block positioned adjacent said guide means for guided verticalmovement therealong, manually operable means associated with saidsupport block to provide vertical movement thereof inoppositedirections, a horizontal shaft extending in a transverse direction withrespect to said work support and rotatably carried by said supportblock, an arm fixed to said shaft at the end thereof adjacent said worksupport extending radially therefrom in a generally upward direction, arotatable grinding wheel mounted on said arm in spaced relation abovethe axis of rotation of said shaft and with its axis of rotationparallel to that of said shaft, means for automatically oscillating saidarm about the axis of rotation of said shaft between limiting positionsat opposite sides of a vertical position, and means responsive to theoscillation of said arm for automatically moving said support blockdownward a predetermined amount on said arm reaching each limitingposition in the oscillation thereof to. feed said grinding wheel into. aworkpiece positioned on said work support while maintaining the radialdimension between theshaft and grinding wheel so that a crown having apredetermined surface contour will be formed on said workpiece.

12. In a grinding machine, a bed, a work support mounted on said bed,guide means mounted on said bed in spaced relation to said work support,a support block positioned adjacent said guide means for guided movementtherealong, a horizontal shaft extending in a transverse direction withrespect to said work support and rotatably carried by said supportblock, an arm fixed to said shaftextending radially therefrom in agenerally upward direction, a motor mounted on said arm for verticalsliding movement thereal'ong, means for producing sliding movement ofsaid motor along said arm, a spindle secured to and driven by saidmotor, a rotatable grinding wheel mounted on said spindle in spacedrelation above the axis of rotation of said shaft and with its axis ofrotation parallel to that of said shaft, means for automaticallyoscillating said arm about the axis of rotation of said shaft betweenlimiting positions at opposite sides of a vertical position, and meansresponsive to the oscilla tion of said arm for automatically moving saidsupport block downward a predetermined amount on said arm reaching eachlimiting position in the oscillation thereof to feed said grinding wheelinto a workpiece positioned on said work support whilemaintaining theradial dimension between the shaft and grinding wheel so that a crownfihaving a predetermined surface contour will be formed on saidworkpiece. V

13. Guide means, a support positioned adjacent said guide means forguided movement therealong, a rotatable grinding wheel carried by saidsupport, means foroscillating said grinding wheel about an axis parallelto the axis of rotation thereof, and automatic means for moving saidsupport alongsaid guide means betwee'ri' separate support apredeterminedamount on 'said' grinding wheel reaching each limiting position in theoscillation thereof to feed said grinding wheel into a workpiece whilemaintaining the dimension between the grinding wheel and axis ofoscillation thereof so that a crown having a predetermined shrfacecontour will be formed on said workpiece.

References Cited in the file of this patent UNITED STATES PATENTS398,741 Morrison et a1. Feb. 26, 1889 918,769 Sachs -Apr. 20, 19092,206,842 Indge July 2Q194O 2,392,819

Y Gruenberg et al. J an. 15, 19 46

